dom4j에서 XPath를 사용하는 간단한 예

package com.wzh.test.xpath;
 
import java.io.File;
 
import org.dom4j.Document;
import org.dom4j.DocumentException;
import org.dom4j.Node;
import org.dom4j.io.SAXReader;
 
public class Demo4 {
 
  public static void main(String[] args) throws DocumentException {
    SAXReader reader=new SAXReader();
    Document document=reader.read(new File("src/book.xml"));
     
    String value=document.selectSingleNode("//书名").getText();
    System.out.println(value);
     
     
    //检测xml文档是否有匹配的用户名和密码
    String username="aaa";
    String password="123";
    reader=new SAXReader();
    document=reader.read(new File("src/users.xml"));
    Node node=document.selectSingleNode("//user[@username='"+username+"'" +
        " and @password='"+password+"']");
    if(node==null)
    {
      System.out.println("用户名密码错误");
    }
    else
    {
      System.out.println("登录成功");
    }
  }
}